Survival and growth of Salmonella Enteritidis PT 30 in almond orchard soils.
نویسندگان
چکیده
AIMS To evaluate factors potentially contributing to the long-term persistence of Salmonella enterica serovar Enteritidis phage type (PT) 30 in an almond orchard. METHODS AND RESULTS Surface and subsurface soil temperatures, and air temperatures in a radiation shelter, were recorded during a 12-month period, and were used to identify relevant storage temperatures (20 or 35 degrees C) for microcosms of two different soil types (clay and sandy loams) with moisture levels near saturation or near field capacity. Salmonella Enteritidis PT 30 was inoculated into the microcosms at 6 log CFU g(-1) dry weight. Between 14 and 180 days of incubation, counts of S. Enteritidis PT 30 decreased rapidly at 35 degrees C and were significantly different (P < 0.05) from counts at 20 degrees C, regardless of the soil type or moisture level. Salmonella was detected by enrichment of 10-g samples from all microcosms after 180 days of incubation at 20 degrees C, but from none of the microcosms held at 35 degrees C. To measure the potential for the growth of S. Enteritidis PT 30 in clay loam soil, an aqueous extract of almond hulls (containing 1.6% mono and disaccharides) or equivalent volume of water was added 7 days after inoculation. Significant (P < 0.05) growth of S. Enteritidis PT 30 was observed within 8 or 24 h of adding hull extract, but not water, to soil. CONCLUSIONS Opportunities may exist for S. Enteritidis PT 30 to survive for an extended time in almond orchard soils and to grow in these soils where hull nutrients are released. SIGNIFICANCE AND IMPACT OF THE STUDY Temperature has a significant impact on the long-term survival of S. Enteritidis PT 30 in soil, and nutrients leached from almond hulls may result in Salmonella growth. These factors should be considered in the design of Good Agricultural Practices for almonds.
منابع مشابه
Salmonella Enteritidis Phage Type 30 from a Single Almond Orchard over a 5-Year Period
In 2001, Salmonella Enteritidis phage type (PT) 30 was isolated from drag swabs of 17 61-ha almond orchards on three farms linked to an outbreak of salmonellosis associated with consumption of raw almonds. The objective of this study was to evaluate the long-term persistence of Salmonella Enteritidis PT 30 in one of the almond orchards associated with the outbreak. Swabs (gauze saturated with f...
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In 2001, Salmonella Enteritidis phage type (PT) 30 was isolated from drag swabs of 17 61-ha almond orchards on three farms linked to an outbreak of salmonellosis associated with consumption of raw almonds. The objective of this study was to evaluate the long-term persistence of Salmonella Enteritidis PT 30 in one of the almond orchards associated with the outbreak. Swabs (gauze saturated with f...
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Thermal inactivation of Salmonella enteritidis PT 30 in almond kernels as influenced by water activity.
Salmonellosis outbreaks related to consumption of raw almonds have encouraged the scientific community to study the inactivation kinetics of pathogens in this dry commodity. However, the low moisture content of the product presents a challenge for thermal control, because the time required to achieve the desired thermal inactivation of microorganisms increases sharply with reduced moisture con...
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A dry-inoculation method for almonds and walnuts was developed to eliminate the need for the postinoculation drying required for wet-inoculation methods. The survival of Salmonella enterica Enteritidis PT 30 on wet- and dry-inoculated almond and walnut kernels stored under ambient conditions (average: 23 °C; 41 or 47% RH) was then compared over 14 weeks. For wet inoculation, an aqueous Salmonel...
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ورودعنوان ژورنال:
- Journal of applied microbiology
دوره 104 5 شماره
صفحات -
تاریخ انتشار 2008